Math Problem Statement

What is an equation for the line that passes through the given coordinates?

Solution

Let's solve these questions one by one. These are all about finding the equation of a line that passes through two given points. The general form of the equation of a line is:

y=mx+by = mx + b

Where:

  • mm is the slope of the line.
  • bb is the y-intercept.

To find mm (slope), we use the formula:

m=y2y1x2x1m = \frac{y_2 - y_1}{x_2 - x_1}

Once the slope is found, we can substitute one point into the equation to solve for bb.


1) What is an equation for the line that passes through the coordinates (2,7) and (0,1)?

Step 1: Find the slope

Using the points (2,7) and (0,1):

m=7120=62=3m = \frac{7 - 1}{2 - 0} = \frac{6}{2} = 3

Step 2: Find the equation

Substitute the point (0,1) into y=3x+by = 3x + b:

1=3(0)+bb=11 = 3(0) + b \quad \Rightarrow \quad b = 1

So, the equation of the line is:

y=3x+1y = 3x + 1


2) What is an equation for the line that passes through the coordinates (2,0) and (0,3)?

Step 1: Find the slope

Using the points (2,0) and (0,3):

m=0320=32m = \frac{0 - 3}{2 - 0} = \frac{-3}{2}

Step 2: Find the equation

Substitute the point (0,3) into y=32x+by = -\frac{3}{2}x + b:

3=32(0)+bb=33 = -\frac{3}{2}(0) + b \quad \Rightarrow \quad b = 3

So, the equation of the line is:

y=32x+3y = -\frac{3}{2}x + 3


3) What is an equation for the line that passes through the coordinates (-1,2) and (7,6)?

Step 1: Find the slope

Using the points (-1,2) and (7,6):

m=627(1)=48=12m = \frac{6 - 2}{7 - (-1)} = \frac{4}{8} = \frac{1}{2}

Step 2: Find the equation

Substitute the point (-1,2) into y=12x+by = \frac{1}{2}x + b:

2=12(1)+b2=12+bb=2+12=522 = \frac{1}{2}(-1) + b \quad \Rightarrow \quad 2 = -\frac{1}{2} + b \quad \Rightarrow \quad b = 2 + \frac{1}{2} = \frac{5}{2}

So, the equation of the line is:

y=12x+52y = \frac{1}{2}x + \frac{5}{2}


4) Find the equation of the line that passes through the points (1,1) and (3,5).

Step 1: Find the slope

Using the points (1,1) and (3,5):

m=5131=42=2m = \frac{5 - 1}{3 - 1} = \frac{4}{2} = 2

Step 2: Find the equation

Substitute the point (1,1) into y=2x+by = 2x + b:

1=2(1)+bb=12=11 = 2(1) + b \quad \Rightarrow \quad b = 1 - 2 = -1

So, the equation of the line is:

y=2x1y = 2x - 1


5) Find the equation of the line that passes through the points (1,3) and (2,4).

Step 1: Find the slope

Using the points (1,3) and (2,4):

m=4321=11=1m = \frac{4 - 3}{2 - 1} = \frac{1}{1} = 1

Step 2: Find the equation

Substitute the point (1,3) into y=x+by = x + b:

3=1(1)+bb=31=23 = 1(1) + b \quad \Rightarrow \quad b = 3 - 1 = 2

So, the equation of the line is:

y=x+2y = x + 2


Would you like any further details on these steps?

Here are 5 related questions to explore further:

  1. How do you derive the slope formula for a line between two points?
  2. What is the geometric interpretation of a slope of 0 or an undefined slope?
  3. How do you find the equation of a line parallel to a given line?
  4. How do you find the equation of a line perpendicular to a given line?
  5. How can you convert a linear equation into slope-intercept form from point-slope form?

Tip: Remember, the slope mm tells you how steep the line is. A positive slope means the line rises as you move right, while a negative slope means it falls.

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations
Coordinate Geometry

Formulas

Slope formula: m = (y2 - y1) / (x2 - x1)
Equation of a line: y = mx + b

Theorems

Slope-Intercept Form
Point-Slope Formula

Suitable Grade Level

Grades 9-12